The advantages to being a Singapore PR centers around the ability to enjoy the right to live, work and integrate into the fabric of Singaporean society just like ordinary citizens. As a Singapore PR, one stand to enjoy many things from Visa/Family/Career Flexibility, Educational/Medical and Housing perks, Tax reliefs, and of course, a natural progression towards Citizenship.
The disadvantages are few but this is subjective. As a neutral taking into consideration all factors, the only disadvantage comes when one decides to renounce their PRs. As Singapore has a lean population, there will always be talents attracted to PR, thus making it hard for individuals who have renounced their PR to attain PR once again. Besides that, Singapore relies on a conscripted defence force. All healthy male PRs, like Citizens, will have to serve their National Service responsibilities upon reaching the required age although deferment for studies are generally allowed.